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Helium Ions (He II) in the Sun's Atmosphere

All stars are made up mostly of hydrogen and helium. Since atoms in the Sun's atmosphere are extremely hot, they move around very, very quickly. The atoms often collide, and such collisions can knock electrons loose from an atom. Atoms with missing (or extra!) electrons are called ions. A helium (chemical element symbol He) atom that is missing one electron is called He II. Normal, neutral helium atoms that still have both electrons are called He I.

Helium is a very rare element on Earth. Because it is lighter than air, helium is used to inflate balloons. Helium holds on to its electrons very strongly, making it extremely difficult to ionize. As a result of this, helium does not react easily with other chemicals.

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